If you aren't very experienced with rabbits yet, you may
  wonder why you should spay (females) or neuter (males) your
  pet rabbit. But it is very important for your rabbit's
  health and likely long life, as well as your long and happy
  experience with your pet, especially if your rabbit is a
  house rabbit.
  
  Some important reasons to spay or neuter your house rabbits
  include:
  
  1. Stop the increase in unwanted bunnies. Rescue
  organizations are full and your babies might wind up
  mistreated or even fed to other animals as food.
  
  2. Help prevent diseases of the reproductive system. Some
  rabbit breeds are very prone to uterine cancer. Plus, any
  fertile female rabbit is also more likely to get ovarian
  disease, mammary gland tumors and cancers, endometriosis,
  and pyometra, false pregnancies. 
  
  Un-neutered males are more vulnerable to infections of the
  reproductive glands, especially if they are allowed to fight
  with other males.
  
  
  
  
  3. Help to prevent behavior problem caused by hormones.
  
  Behavior problems related to breeding and mating issues may
  include:
  
  a. Spraying urine or refusing litter box 
  training -Mature
  rabbits of both genders will spray urine on vertical surfaces
  mark their territories, and if it goes on for too long even
  spaying and neutering may not break the habit.
  
  b. Fighting and aggression - Nearly all 
  aggression against
  other rabbits or humans, and fighting between rabbits is
  territorial. And nearly all territorial issues in rabbits
  are related to mating. So early neutering and spaying can
  keep both you and your rabbits from potential injury.
  
  c. Chewing - All rabbits gnaw, but it has 
  been observed by
  many rabbit owners that excessive or problem gnawing is
  greatly improved within a few weeks or months of spaying or
  neutering.
  
  d. Odor - Breeding mature animals of most 
  species have
  strong smelling urine, and rabbits are no exception.
  Neutering or spaying your house rabbits should greatly
  improve the atmosphere in your home.